package org.expeditee.core;

import org.expeditee.core.bounds.AxisAlignedBoxBounds;

/**
 * Class for anchoring the position of items within the frame.
 * Anchoring is when the position of the item is defined relative
 * to the edge of the frame instead of being defined in absolute
 * coordinates. Can't be anchored to the left and right edge at
 * the same time, nor the top and bottom edge at the same time.
 * 
 * @author cts16
 */
public class Anchoring {

	/** The relative distance from the left or right edge (null means unanchored). */
	private Integer _xAnchor = null;
	/** The relative distance from the top or bottom edge (null means unanchored). */
	private Integer _yAnchor = null;
	/** Whether the x-anchor is relative to the left or right edge. */
	private boolean _left = true;
	/** Whether the y-anchor is relative to the top or bottom edge. */
	private boolean _top = true;
	
	public Anchoring()
	{
	}
	
	public void setXAnchor(Integer offset, boolean left)
	{
		_xAnchor = offset;
		_left = left;
	}
	
	public void setYAnchor(Integer offset, boolean top)
	{
		_yAnchor = offset;
		_top = top;
	}
	
	public void setXAnchor(Anchoring other)
	{
		if (other == null) return;
		
		setXAnchor(other._xAnchor, other._left);
	}

	public void setYAnchor(Anchoring other)
	{
		if (other == null) return;
		
		setYAnchor(other._yAnchor, other._top);
	}
	
	public void setLeftAnchor(Integer offset)
	{
		setXAnchor(offset, true);
	}
	
	public void setRightAnchor(Integer offset)
	{
		setXAnchor(offset, false);
	}
	
	public void setTopAnchor(Integer offset)
	{
		setYAnchor(offset, true);
	}
	
	public void setBottomAnchor(Integer offset)
	{
		setYAnchor(offset, false);
	}
	
	public void removeXAnchor()
	{
		setXAnchor(null, _left);
	}
	
	public void removeYAnchor()
	{
		setYAnchor(null, _top);
	}
	
	public void removeAllAnchors()
	{
		removeXAnchor();
		removeYAnchor();
	}
	
	public Integer getXPositionInBox(AxisAlignedBoxBounds box)
	{
		if (box == null || _xAnchor == null) return null;
		
		if (_left) {
			return box.getMinX() + _xAnchor;
		} else {
			return box.getMaxX() - _xAnchor;
		}
	}
	
	public Integer getYPositionInBox(AxisAlignedBoxBounds box)
	{
		if (box == null || _yAnchor == null) return null;
		
		if (_top) {
			return box.getMinY() + _yAnchor;
		} else {
			return box.getMaxY() - _yAnchor;
		}
	}
	
	public Point getPositionInBox(AxisAlignedBoxBounds box)
	{
		Integer x = getXPositionInBox(box);
		Integer y = getYPositionInBox(box);
		
		if (x == null || y == null) return null;
		
		return new Point(x, y);
	}
	
	public boolean isXAnchored()
	{
		return _xAnchor != null;
	}
	
	public boolean isYAnchored()
	{
		return _yAnchor != null;
	}
	
	public boolean isAnchored()
	{
		return isXAnchored() || isYAnchored();
	}
	
	public Integer getLeftAnchor()
	{
		return _left ? _xAnchor : null;
	}
	
	public Integer getRightAnchor()
	{
		return !_left ? _xAnchor : null;
	}
	
	public Integer getTopAnchor()
	{
		return _top ? _yAnchor : null;
	}
	
	public Integer getBottomAnchor()
	{
		return !_top ? _yAnchor : null;
	}
}